From e7c5fa3c9e15d1ad7c4d284c90a97ee61e0dcb67 Mon Sep 17 00:00:00 2001
From: Arthur Lafrance <lafrancearthur@gmail.com>
Date: Fri, 5 Nov 2021 13:19:11 -0700
Subject: [PATCH] impl'd rehash and updated tests

---
 src/lfc/collections/map.c             | 35 +++++++++++++++++++++------
 src/lfc/collections/tests/map_tests.c |  2 +-
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/src/lfc/collections/map.c b/src/lfc/collections/map.c
index 497b80c..501d5c0 100644
--- a/src/lfc/collections/map.c
+++ b/src/lfc/collections/map.c
@@ -6,6 +6,8 @@
 #include "internals/collections/__mapbucket.h"
 
 #include "lfc/collections/array.h"
+#include "lfc/collections/set.h"
+
 #include "lfc/utils/pair.h"
 #include "lfc/utils/panic.h"
 
@@ -31,21 +33,19 @@ void hashmap_free(hashmap_t* map, free_fn_t key_free, free_fn_t val_free) {
     array_free(&map->buckets, NULL);
 }
 
-size_t hashmap_bucket(hashmap_t* map, void* key) {
+size_t __hashmap_bucket(hashmap_t* map, void* key) {
     return (map->hash_fn)(key) % map->buckets.len;
 }
 
 void* hashmap_get(hashmap_t* map, void* key) {
-    size_t bucket_index = hashmap_bucket(map, key);
+    size_t bucket_index = __hashmap_bucket(map, key);
     struct __mapbucket* bucket = array_at(&map->buckets, bucket_index);
 
     return __mapbucket_find(bucket, key, map->key_eq);
 }
 
-// TODO: rehash
-
 uint8_t hashmap_set(hashmap_t* map, void* target_key, void* new_value, free_fn_t val_free) {
-    size_t bucket_index = hashmap_bucket(map, target_key);
+    size_t bucket_index = __hashmap_bucket(map, target_key);
     struct __mapbucket* bucket = array_at(&map->buckets, bucket_index);
 
     for (struct __mapbucket_node* node = bucket->head; node != NULL; node = node->next) {
@@ -73,9 +73,30 @@ uint8_t hashmap_contains(hashmap_t* map, void* key) {
     return hashmap_get(map, key) != NULL;
 }
 
+void __hashmap_rehash(hashmap_t* map) {
+    array_t old_buckets = map->buckets;
+    hashmap_init(map, old_buckets.len * 2, map->hash_fn, map->key_eq);
+
+    for (size_t i = 0; i < old_buckets.len; i++) {
+        struct __mapbucket* bucket = array_at(&old_buckets, i);
+
+        for (struct __mapbucket_node* node = bucket->head; node != NULL; node = node->next) {
+            hashmap_insert(map, node->data.first, node->data.second);
+        }
+
+        __mapbucket_free(bucket, NULL, NULL);
+    }
+
+    array_free(&old_buckets, NULL);
+}
+
 uint8_t hashmap_insert(hashmap_t* map, void* key, void* val) {
     if (!hashmap_contains(map, key)) {
-        size_t bucket_index = hashmap_bucket(map, key);
+        if (hashmap_load_factor(map) > MAX_LOAD_FACTOR) {
+            __hashmap_rehash(map);
+        }
+
+        size_t bucket_index = __hashmap_bucket(map, key);
         struct __mapbucket* bucket = array_at(&map->buckets, bucket_index);
 
         __mapbucket_prepend(bucket, key, val);
@@ -88,7 +109,7 @@ uint8_t hashmap_insert(hashmap_t* map, void* key, void* val) {
 }
 
 void hashmap_remove(hashmap_t* map, void* key, free_fn_t key_free, free_fn_t val_free) {
-    size_t bucket_index = hashmap_bucket(map, key);
+    size_t bucket_index = __hashmap_bucket(map, key);
     struct __mapbucket* bucket = array_at(&map->buckets, bucket_index);
 
     if (__mapbucket_remove(bucket, key, map->key_eq, key_free, val_free)) {
diff --git a/src/lfc/collections/tests/map_tests.c b/src/lfc/collections/tests/map_tests.c
index 1eedb80..6a43c81 100644
--- a/src/lfc/collections/tests/map_tests.c
+++ b/src/lfc/collections/tests/map_tests.c
@@ -139,7 +139,7 @@ void test_hashmap_multiple_distinct_values_inserted_correctly() {
 
         assert(hashmap_contains(&map, keys + i % str_len));
         assert_eq(map.size, i + 1);
-        assert_eq(hashmap_load_factor(&map), (i + 1.0) / DEFAULT_BUCKETS); // TODO: update for rehash
+        assert_eq(hashmap_load_factor(&map), (i + 1.0) / map.buckets.len); 
         assert_false(hashmap_is_empty(&map));
     }